Flexion is defined as what happens to the angle between the bones at a joint?

• A. Angle decreases
• B. Angle increases
• C. No change
• D. Rotation

Answer: (A)

Flexion involves bending a joint so the two bones move closer together, which reduces the angle between them. When you bend your elbow, for example, the angle between the upper arm and the forearm becomes smaller, illustrating a decrease in joint angle. This is the defining action of flexion. Extension is the opposite, increasing the angle back toward or beyond the straight position. Rotation is a different movement that turns a bone around its axis rather than simply changing the angle between the two bones.